Mbengue Babacar, Niang Birahim, Diatta Bacary, Tall Adama, Garraud Olivier, Perraut Ronald, Dieye Alioune
Laboratoire d'Immunologie, Faculté de Médecine, de Pharmacie et d'Odontostomatologie, Université Cheikh Anta Diop de Dakar, Senegal, e-mail:
Iran J Immunol. 2010 Sep;7(3):150-61.
Cerebral malaria (CM) is one of the major causes of death in African populations infected with Plasmodium falciparum. Only 1% of infected subjects develop CM. The reasons for these differences are not fully understood, but it is likely that the host humoral response against blood-stage antigens plays a role in protection from malaria, although the precise targets and mechanisms mediating immunity remain unclear.
The purpose of this study was to distinguish between defined P. falciparum-specific Ab response patterns in patients presenting with mild malaria (MM) vs. CM.
We used a panel of P. falciparum conserved antigens including crude blood-stage extracts schizont, merozoite and parasitised erythrocyte membranes and MSP-1p19, PfEB200, R23 and GST-5 recombinant antigens in a retrospective case-control study of symptomatic adults, one group presenting confirmed CM without fatal outcome and another group with MM. We further matched P. falciparum-specific Ab responses with those from individuals living in an endemic setting known to have protective immunity and considered them as "immune control" subjects (IC). Total IgG, IgM and IgG subclass Ab responses were determined using ELISA method.
Substantial Ab responses were found in symptomatic patients, significantly lower than the "immune control" subjects, and with a limited quantitative difference between MM versus CM. Interestingly, asynchronous IgM response was evidenced in CM contrary to MM.
Our results suggest that the contribution of an efficient IgG response against parasite multiplication is of importance in the evolution towards CM manifestation without fatal outcome and deserves further analysis for vaccine candidates.
脑型疟疾（CM）是感染恶性疟原虫的非洲人群的主要死亡原因之一。仅有1%的感染者会发展为脑型疟疾。这些差异的原因尚未完全明确，但宿主针对血期抗原的体液反应可能在预防疟疾中发挥作用，尽管介导免疫的精确靶点和机制仍不清楚。
本研究的目的是区分出现轻度疟疾（MM）和脑型疟疾的患者中明确的恶性疟原虫特异性抗体反应模式。
在一项针对有症状成年人的回顾性病例对照研究中，我们使用了一组恶性疟原虫保守抗原，包括粗制血期提取物、裂殖体、裂殖子和被寄生红细胞膜，以及MSP-1p19、PfEB200、R23和GST-5重组抗原，一组为确诊的无致命结局的脑型疟疾患者，另一组为轻度疟疾患者。我们还将恶性疟原虫特异性抗体反应与已知具有保护性免疫力的流行地区个体的反应进行了匹配，并将他们视为“免疫对照”受试者（IC）。使用酶联免疫吸附测定法测定总IgG、IgM和IgG亚类抗体反应。
在有症状的患者中发现了大量抗体反应，显著低于“免疫对照”受试者，且轻度疟疾与脑型疟疾之间的定量差异有限。有趣的是，与轻度疟疾相反，脑型疟疾中出现了异步IgM反应。
我们的结果表明，针对寄生虫增殖的高效IgG反应在向无致命结局的脑型疟疾表现演变过程中具有重要作用，值得对候选疫苗进行进一步分析。
